基于Hock-Brown准则的层状岩体隧道开挖响应分析

利用Hoek-Brown准则描述岩体的强度特征,并建立相应隧道开挖的数值计算模型,分析不同侧压系数时层状岩体的变形破坏特征.研究结果表明,隧道边墙水平位移随侧压系数K的增大而增大,但当K为2.0-2.5时,位移随侧压系数的变化幅度逐渐减小;顺层岩体一侧的水平位移大于逆层一侧的水平位移;当侧压系数较小时,顶板沉降量大于底板回弹量,当侧压系数较大时,二者之间的差别较小;隧道围岩的破坏形式包括剪切破坏和拉伸破坏,当侧压系数较小时,破坏区域较小,主要位于隧道的左上部;随着侧压系数的增大,围岩的破坏区域逐渐增大,但主要部位仍位于隧道的左上部,而右上部的破坏区域较小.

Excavation response of tunnel in stratified rock mass based on Hoek-Brown criterion

Hoek-Brown criterion was used to describe the strength characteristic of rock mass, and the numerical simulation model of tunnel was built to analyze the deformation and failure characteristic of stratified rock mass with different side-pressure coefficients K. The results show that the maximum horizontal displacements of side wall as well as maximum vertical displacements of roof and floor of surrounding rock mass increase with the increase of AT, but when K varies in 2.0-2.5, the increase range of displacement reduces gradually. The horizontal displacement for the inclined stratified rock mass is larger than that for the inverse inclined rock mass. When K is small, the settlement of the roof is larger than that of the floor rebound of tunnel, and the difference between them is smaller when K becomes larger. The failure mode of surrounding rock mass for tunnel consists of shear failure and tensile failure. When K is small, the failure area is small and exists in the top left of tunnel, the failure areas of rock mass become larger with the increase of AT, and the main areas are located on the top left of tunnel with few failure areas located on the top right.